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Design and Simulation of Two Stroke Engines

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<strong>Design</strong> <strong>and</strong> <strong>Simulation</strong> <strong>of</strong> <strong>Two</strong>-<strong>Stroke</strong> <strong>Engines</strong><br />

temperature Tj = TQXJ (2.18.25)<br />

particle velocity cs = G5a0(xp - Xq) (2.18.26)<br />

2.18.5 Singularities during the interpolation procedure<br />

It is obvious that arithmetic problems could arise with the procedure given in Sec. 2.18.4<br />

if the values <strong>of</strong> XR <strong>and</strong> XRI, or the values <strong>of</strong> XL <strong>and</strong> XLI, are equal. This would certainly be<br />

true in a model start-up situation, where the pipes would be "dead" <strong>and</strong> all <strong>of</strong> the array elements<br />

<strong>of</strong> pressure amplitude ratio XR, XRI, XL <strong>and</strong> XLI would be unity. In that situation the<br />

values <strong>of</strong> A <strong>and</strong> B would be zero, C <strong>and</strong> D would be infinity <strong>and</strong> the calculation would<br />

collapse. Therefore, separate solutions are required for the wave pressures, Xp <strong>and</strong> Xq, in<br />

these unique situations, either at start-up or as cover during the course <strong>of</strong> a complete calculation.<br />

The solution is fairly straightforward using Eqs. 2.18.16 <strong>and</strong> 2.18.17, for the three possibilities<br />

(a)-(c) involved.<br />

In case (i) the following is the solution if it is true that XR is equal to XRI:<br />

Hence,<br />

Hence,<br />

Xq =<br />

X p = X R1<br />

1 + D + G4Xj<br />

In case (ii) the following is the solution if it is true that XL is equal to XLI:<br />

X P =<br />

x q = XLI<br />

1 + C + G4XC<br />

G* + 1<br />

(2.18.27)<br />

(2.18.28)<br />

(2.18.29)<br />

(2.18.30)<br />

In case (iii) the following is the solution if it is true that XR is equal to XRI <strong>and</strong> also that<br />

XL is equal to XLI :<br />

<strong>and</strong>,<br />

x q = X LI<br />

Xp = XRI<br />

150<br />

(2.18.31)<br />

(2.18.32)

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